Not applicable.
This invention relates to golf club heads; specially to an improved clubhead for putters.
Golfers, for centuries, have been struggling for greater distance, accuracy, and consistency on their golf shots. Therefore, inventors have created hundreds (perhaps thousands) of different types of golf clubs to improve these functions by providing:
1. More effective results from imperfect shots, to achieve more consistency;
2. Better alignment features, to improve accuracy;
3. Greater efficiency for the club ball strike, to increase distance.
I Off-center club ball impact constitutes a large percentage of imperfect golf shots. A ball that is struck away from the sweetspot, deflects the club at impact. The force of the ball-club contact towards the toe or the heel causes the clubhead to open or close, sending the ball away from the intended target line, resulting in misdirection of the ball and an other than anticipated impact force. Off-center impact is especially important for putters, as even a slight deflection can cause a loss of a stroke. A great majority of golfers tend to miss the sweetspot by up to approximately 15 mm for putters, and up to 25 mm for irons and woods (the usual-mis-hit-area). This problem has been attempted and only partially solved by increasing the heel-toe weighting suggested by many previous inventions such as U.S. Pat. No., 226,654, U.S. Pat. No. 3,042,405 Solheim, U.S. Pat. No. 4,243,472, U.S. Pat. No. 4,714,252 Roraback 1987, U.S. Pat. No. 5,816,930, U.S. Pat. No. 5,913,731 Westerman 1999, U.S. Pat. No. 5,951,412, U.S. Pat. No. 5,961,400. Further invention by U.S. Pat. No. 5,766,093 Rohrer, uses many solid layers of different materials situated side-by-side for the club head construction to improve off-center impacts; but this solution is only partially effective in addition to being costly to manufacture. The off-center contact remains one of the worst problems in a golf swing, especially for the higher-handicapped golfer.
II The alignment of the clubhead at address is twofold. It involves lining up the clubface perpendicular to the target and the alignment of the effective center of the clubhead (sweetspot) to the center of the ball, and on the target line. Good alignment is critical, especially for putters. It is a given that occasionally these alignments may be deviated from by the expert golfer for certain types of shots. My experience is that golfers usually use one or more of the following methods to align the clubhead to the ball and the target when addressing the ball:
axe2x80x94Alignment with focus on placing the leading edge of the club positioned at 90 degrees to the ball-target-line (perpendicular aiming). It is not an easy task for most golfers to align the leading edge (perpendicular axis) of a clubhead at exactly 90 degrees to an imaginary target line. It is, however, easier to align a visually strong horizontal axis (positioned parallel to the target), if one was provided. But, a clubhead with the longer axis going towards the target is prohibited by the rules of golf (as governed by the United States Golf Association and the Royal and Ancient Golf Club of St. Andrews). Aligning the clubface perpendicular to the target is made more complex given the fact that the shaft and the clubhead must form an angle (approximately 10 to 40 degrees from vertical). Several T-shaped, U-shaped, H-shaped, and E-shaped putter-heads have been previously invented, U.S. Pat. No. 2,957,696, U.S. Pat. No. 3,758,115, U.S. Pat. No. 3,888,204, U.S. Pat. No. 4,411,430 Dian 1983, U.S. Pat. No. 4,253,667 Clark 1981, U.S. Pat. No. 4,964,639 Tucker 1990, U.S. Pat. No. 5,244,151 Anderson (1994), U.S. Pat. No. 5,890,969 Becher 1999, U.S. Pat. No. 5,993,324 Gammil 1999, U.S. Pat. No. 6,045,453 Jenkins 2000. These clubs provide a long horizontal axis to assist in parallel alignment,; however, due to the wide body shape, an imperfect stroke will tend to catch the bottom of the clubhead on the ground prior to contact with the ball. Other problems with the above teachings are that the face of the club (perpendicular member) is still a dominant visual feature which contradicts the provided horizontal axis. Additionally, in these inventions the horizontal member is made solid, placing the weight of the clubhead centered directly behind the ball. With this weight behind the sweetspot, the golfer will experience a heavy impact when the ball is stroked on the sweetspot; but will lose distance and accuracy when the ball is struck away from the center, on the perimeter of the sweetspot. Many other inventions as in U.S. Pat. No. 3,206,755; U.S. Pat. No. 3,679,207; U.S. Pat. No. 5,700,206, propose a croquet style of putter clubhead and stroke which is not within the current rules of golf.
bxe2x80x94Alignment using any available lines, dots, or other markings provided on top or face of the club designating the club""s sweetspot, parallel and on the ball target line (parallel aiming). Conventional markings on top or on the face of clubs give a skewed perspective from the golfer""s view at address position (standing to the side of the ball-target line), especially for irons and woods since the golfer is standing farther from the ball. In addition, the markings on the club in some cases do not represent the true center of the clubhead.
cxe2x80x94Alignment using the overall shape of the club (the entire clubhead). Some golfers tend to place the club behind the ball without specific regard to any provided markings or the leading edge of the club. Conventional clubheads do not provide an intuitive alignment feature to assist these golfers in making a precise alignment using the overall clubhead shape.
In addition to the above alignment techniques, the sole (bottom) of the clubs have been traditionally constructed relatively flat or with a slight curve, therefore, not of significant help to the golfer with alignment. It is well documented that the golfers of all abilities continue to have difficulty with their club alignments.
III Efficiency of the strike depends partly on the effectiveness of the golfer""s swing. It is generally accepted that in an effective golf swing, especially in a putting stroke, the clubhead should remain on the intended swing plane arc and not easily go off track. In addition, during the swing the club should go back slower on the back swing than it goes forward in the forward swing. Conventional clubheads do not provide sufficient assistance to the golfer in taking the club back slower on the backswing, and lack adequate aerodynamic qualities to prevent the club from going off-track while the club is being swung above ground.
One of the most common problems in a golf stroke, especially in putting, is pulling the clubhead across the ball too quickly to the inside of the target line during impact. Ideally the leading edge of club should stay perpendicular to the target at and immediately after impact with the ball (for a normal shot). The hosel, which is the transition between the shaft and the clubhead, is typically a narrow stem and is not of much assistance in keeping the stroke parallel to the target and keeping the heavy clubhead on track at the moment of contact with the ball, especially on off-center hits. An example of a conventional hosel can be found in U.S. Pat. Nos. D20926, 4,512,577, and 5,769,736.